1. Field of Invention
The present invention relates to detection and mapping of hydrocarbon reservoirs using radar techniques.
2. Description of Prior Art
In the past, there have generally been two predominant types of detection and mapping techniques for hydrocarbon reservoirs using wave energy. One of these, and currently the most widely used, has been based on acoustic or seismic energy waves, whether in reflection or refraction surveying. Seismic exploration is generally time consuming and expensive, requiring extensive arrays of sensing geophones or transducers to be placed over considerable areas.
The other wave energy detection technique for hydrocarbon reservoirs has been based on the use of electromagnetic energy, or radar waves. A considerable body of prior art exists based on the assumption that the presence of subsurface hydrocarbon reservoirs caused an identifiable, discernable presence of escaping gases in the atmosphere at the earth's surface.
A great deal of thought and effort has been spent on attempts to detect and identify these escaping gases. It was supposed that both the presence and type of gas escaping from the earth could be detected based on unique radar-identifiable molecular characteristics of the different species of gases. Examples in this area includes U.S. Pat. Nos. 3,651,395; 4,100,481; 4,132,943; 4,385,516 and 4,504,833.